Higher Plaque Burden Research Articles

Characteristics of coronary artery disease in symptomatic type 2 diabetic patients: evaluation with CT angiography

BackgroundCoronary artery disease (CAD) is a common and severe complication of type 2 diabetes mellitus (DM). The aim of this study is to identify the features of CAD in diabetic patients using coronary CT angiography (CTA).MethodsFrom 1 July 2009 to 20 March 2010, 113 consecutive patients (70 men, 43 women; mean age, 68 ± 10 years) with type 2 DM were found to have coronary plaques on coronary CTA. Their CTA data were reviewed, and extent, distribution and types of plaques and luminal narrowing were evaluated and compared between different sexes.ResultsIn total, 287 coronary vessels (2.5 ± 1.1 per patient) and 470 segments (4.2 ± 2.8 per patient) were found to have plaques, respectively. Multi-vessel disease was more common than single vessel disease (p < 0.001), and the left anterior descending (LAD) artery (35.8%) and its proximal segment (19.1%) were most frequently involved (all p < 0.001). Calcified plaques (48.8%) were the most common type (p < 0.001) followed by mixed plaques (38.1%). Regarding the different degrees of stenosis, mild narrowing (36.9%) was most common (p < 0.001); however, a significant difference was not observed between non-obstructive and obstructive stenosis (50.4% vs. 49.6%, p = 0.855). Extent of CAD, types of plaques and luminal narrowing were not significantly different between male and female diabetic patients.ConclusionsCoronary CTA depicted a high plaque burden in patients with type 2 DM. Plaques, which were mainly calcified, were more frequently detected in the proximal segment of the LAD artery, and increased attention should be paid to the significant prevalence of obstructive stenosis. In addition, DM reduced the sex differential in CT findings of CAD.

Effect of Vessel Size on Lipid Content of Coronary Plaques Assessed by Integrated Backscatter Intravascular Ultrasound

Tissue characterization of coronary plaques is feasible using integrated backscatter intravascular ultrasound (IB-IVUS), and higher lipid content has been found in the target lesions of acute coronary syndrome (ACS). The present study was performed to identify clinical and IVUS parameters that correlate with plaque composition assessed by IB-IVUS. A total of 109 patients (age 60.0+/-9.7 years) were evaluated with IVUS and IB-IVUS prior to percutaneous coronary intervention. Patients with ACS had a larger vessel size and higher plaque burden in the target lesion than those with stable angina. Relative lipid content of the target lesion by IB-IVUS was also higher in ACS (43.6%+/-12.0% vs 29.9%+/-14.2%; P<0.001). The remodeling index (r=0.403, P<0.001), plaque burden (%) (r=0.495, P<0.001), and vessel size (r=0.572, P<0.001) significantly correlated with lipid content. In the multiple regression analysis, vessel size was the most important independent predictor of lipid content followed by presence of ACS and the remodeling index. ACS, positive remodeling, and larger plaque burden were associated with higher lipid content of coronary plaque. However, the lipid content on IB-IVUS was also significantly affected by vessel size. Therefore, qualitative, morphologic assessment of coronary plaque rather than simple quantitative analysis of tissue components seems to be more appropriate for the identification of vulnerable plaque using IB-IVUS.

Plaque type and composition as evaluated non-invasively by MSCT angiography and invasively by VH IVUS in relation to the degree of stenosis

Background:Imaging of coronary plaques has traditionally focused on evaluating degree of stenosis, as the risk for adverse cardiac events increases with stenosis severity. However, the relation between plaque composition and...

Abstract 4917: Clopidogrel Resistance and Coronary Artery Plaque Burden in Patients Undergoing Percutaneous Coronary Intervention

Background: Clopidogrel anti-inflammatory effect and plaque burden are important factors for atherothrombotic process. Data are lacking on relationship of plaque burden and clopidogrel resistance in patients undergoing percutaneous coronary intervention (PCI) Methods: We identified 138 patients who had intravascular ultrasound during PCI between Jan 2007 to June 2007. Using the Verify Now Point-of-care assay, P2Y12 platelet reaction units (PRU) and percent inhibition of platelet activation (IPA) were measured 16 –24 hours after the loading dose of clopidogrel (600mg for patients not on clopidogrel daily, and 300mg for patients on clopidogrel 75mg daily) but before the next day of clopidogrel dose. CR was defined as PRU &gt;200 or as IPA&lt;10% or &lt;20%. Results: Mean age of patients was 66±11 years and 74% were males. PRU&gt;200 was found in 53 patients (38.4%) and PRU ≤200 in 85 patients (61.6%). Presence of myocardial infarction, hyperlipidemia, renal disease, smoking history, stable or unstable angina at admission were similar between the PRU groups and between IPA groups. Hypertension, diabetes, older age and reference site plaque burden were higher in clopidogrel resistance (Table ). With use of alternative definitions, reference segment plaque burden was also higher in clopidogrel resistance patients: 0.50±0.12 vs 0.41±0.13 in &lt;10% vs ≥10% platelet inhibition (p=0.05), and 0.49±0.12 vs 0.41±0.13 in &lt;20% vs ≥20% platelet inhibition (p=0.03) Conclusion: Clopidogrel resistance patients have more high risk baseline characteristics and higher plaque burden at the reference vessel segment, implying diffuse intracoronary atherosclerosis compared to clopidogrel sensitive patients who underwent PCI

Serum tissue inhibitor of metalloproteinases-1 and higher risk features of coronary plaque: A volumetric multivessel intravascular ultrasound study

Aims The purpose of this study was to determine the relationship between higher-risk features of coronary plaque and serum levels of matrix metalloproteinase (MMP) family enzymes in the stable angina patients. Methods and results In 36 patients, 75 coronary lesions were assessed by intravascular ultrasound. For each of the plaques remodelling index, mean calcium arc and plaque burden were measured. Positive remodelling and the values of the calcium arc and plaque burden above the respective medians were regarded as the higher-risk features and summarised for each lesion. Serum levels of MMP-2, -3, -7, -9, and tissue inhibitor of MMP (TIMP)-1 and -2 were measured in all patients. TIMP-1 level was the independent predictor of presence of a lesion with positive remodelling (OR 1.032; 95% CI: 1.004–1.061) and of a lesion with higher plaque burden (OR 1.026; 95% CI: 1.003–1.049) in a given patient. Whereas, MMP-2 level was an independent predictor of presence of a lesion with higher calcium arc (OR 1.035; 95% CI: 1.001–1.071). TIMP-1 level ( p = 0.003) was also an independent predictor of a number of higher-risk features in the highest-risk plaque in a given patient. Conclusions TIMP-1 level correlates with clustering of plaque features associated with higher risk of complications in stable angina patients.

Superficial femoral artery: current treatment options

Treatment of the superficial femoral artery (SFA) has been among the least effective of all endovascular procedures in terms of long-term patency. The relatively small vessel lumen, in conjunction with a high plaque burden, slow flow, and a high frequency of primary occlusions, contributes to a considerable rate of acute technical failures. Because of these technical limitations a much effort has been made during the past years. This manuscript should summarize the hopes and limitations of different approaches such as brachytherapy, cutting balloons, stents and stent grafts, drug-eluting stents, and drug-coated balloons.

No change in endothelial-dependent vasomotion late after coronary irradiation

Purpose Mechanical injury from balloon angioplasty and stenting is known to cause prolonged endothelial dysfunction, even distal to the injured segment. Intravascular irradiation therapy is associated with delayed healing response and may therefore also impede endothelial functional recovery. This study was conducted to assess endothelial function late after the irradiation of atherosclerotic coronary arteries. Methods and materials In 15 patients (8 with additional radiation and 7 with stenting only), directly after the intervention and at 6-month follow-up, endothelial function of the distal segment was studied by assessment of coronary diameter after intracoronary acetylcholine (Ach). Coronary flow reserve (CFR) and intravascular ultrasound (IVUS) investigation were performed for unequivocal interpretation of angiographic data. Results No significant different response to Ach could be detected at baseline nor at follow-up (−17±14% vs. −17±15% for radiation vs. nonradiation at baseline, P=1.0; −8±11% vs. −9±13% at follow-up, P=.8). IVUS data revealed more constrictive remodeling in the nonradiation patients, but a minimal increase in mean plaque area in the radiation patients compared with a significant decrease in nonradiation patients (+4% vs. −25%, P=.02). Conclusions Irradiation of atherosclerotic coronary arteries does not affect endothelium-dependent vasodilatation acutely or at 6 months. Irradiated segments demonstrated less negative remodeling but higher plaque burden than the controls did.

Lesion Characteristics in Patients with Acute Coronary Syndrome: A Comparison with Lesion in Patients with Stable Angina by Intravascular Ultrasound

Background and Objectives：The pathophysiology of acute coronary syndrome (ACS) is plaque rupture with thrombus formation, which is different from that of stable angina pectoris (SA). Intravascular ultrasound (IVUS) prior to percutaneous coronary intervention provides information on the plaques and vessel wall itself. The purpose of this study was to evaluate the lesion characteristics of ACS prior to coronary intervention compared to those of SA lesions by IVUS. Subjects and Methods：Pre-interventional IVUS was performed on 68 culprit lesions in 41 ACS and 25 SA patients. The plaque morphology, lumen and vessel sizes, and arterial remodeling pattern at the lesion segment were analyzed in both groups. A plaque rupture was defined as a plaque containing a cavity that communicated with the lumen, which was covered with a fibrous cap. Results：Positive remodeling was more frequent in patients with ACS than those with SA (42 vs. 11%), whereas negative remodeling was more frequent in patients with SA (22 vs. 41%) (p=0.023). Plaque rupture/dissection and thrombus was more frequent (51 vs. 19%, p=0.006 and 39 vs. 4%, p=0.001) in patients with ACS. Lesions with ACS had significantly larger EEM CSA, plaque CSA and plaque burden (p<0.05). There were no significant differences in the clinical parameters, angiographic parameters and plaque morphologies. Conclusion：Positive remodeling, plaque rupture/dissection and thrombus were more frequently observed in patients with ACS. In addition, lesions with ACS had a larger vessel size and a higher plaque burden. The type of remodeling, plaque rupture or dissection, thrombus and amount of plaques might have an impact on the clinical presentation. (Korean Circulation J 2004;34(6):548-557)

The prognostic importance of endothelial dysfunction and carotid atheromaburden in patients with coronary artery disease

ObjectivesThe goal of this study was to determine the relative prognostic importance of noninvasive measures of endothelial function and atheroma burden in patients with coronary artery disease (CAD). BackgroundDirect measurement of atherosclerosis by carotid ultrasound and endothelial function assessment by brachial artery flow-mediated dilation (FMD) have both been shown to predict vascular events. The combined prognostic utility of carotid ultrasound and FMD relative to traditional risk markers and cardiovascular fitness has not been evaluated. MethodsA total of 152 patients with CAD underwent metabolic testing, exercise stress tests, carotid ultrasound, and endothelial function measurements. ResultsPatients were followed for 34 ± 10 months during which 22 vascular events occurred. Peak FMD (p = 0.012) and FMD/nitroglycerin-mediated dilation (NMD) ratio (p = 0.008) were lower in subjects with events. Univariate analysis with Cox proportional hazards modeling identified plaque area (p = 0.0047), total area (p = 0.0085), peak FMD (p = 0.01), FMD/NMD ratio (p = 0.008), stress test workload (p = 0.027), long-acting nitroglycerin (NTG) (p = 0.0071), and calcium blockers (p = 0.0057) as predictors of adverse events. Multivariate analysis showed that FMD/NMD ratio (p < 0.0001), carotid plaque area (p = 0.06), and NTG (p = 0.005) were independent predictors. Based on median values, subjects were divided into high and low “plaque burden” groups and into high and low FMD/NMD subgroups. Patients with high FMD/NMD had low event rates irrespective of the degree of carotid atheroma. Patients with low FMD/NMD and high “plaque burden” had the highest event rate (p < 0.05). ConclusionsThe structural and functional status of the vasculature are independent predictors of coronary events as shown by noninvasive measurement of endothelial function and carotid atheroma burden in patients with CAD. Preserved endothelial function attenuates the risk of future events associated with a high plaque burden.

A synergistic approach to optimal stenting: Directional coronary atherectomy prior to coronary artery stent implantation—the AtheroLink registry

OBJECTIVESThe AtheroLink registry sought to observe the effect of plaque burden reduction by directional coronary atherectomy (DCA) prior to stenting on acute lesion minus rate, on the clinical success rate and on the incidence of in-stent restenosis six months after intervention.BACKGROUNDAlthough coronary stenting has reduced restenosis, its effect has been less favorable in complex lesions with a high plaque burden that results from suboptimal stent expansion. Therefore, plaque removal by DCA may improve the results of coronary stenting.METHODSA total of 167 patients with >60% stenosis in a native coronary artery of 2.8 to 4.0 mm in diameter were enrolled in 10 study centers on an intention-to-treat basis. All patients underwent DCA aimed at an optimal result (residual diameter stenosis <20%) followed by stenting. Angiographic follow-up was performed in 120 (71.8%) patients at 5.3 ± 2.8 months.RESULTSLesion success was achieved in 164/167 (98.2%) patients, and the clinical success rate was 95.2% (159/167 patients). The overall restenosis rate in the 120 patients with angiographic follow-up was 10.8% (13/120). Incidence of restenosis was lower (8.4%) in patients with optimal stent deployment following DCA compared to patients with a persisting caliber reduction >15% (restenosis rate 15.3.%) and restenosis occurred with a significantly higher frequency (p < 0.04) in distal lesions (37.5%) compared to proximal stenoses (9.0%).CONCLUSIONSThis observational multicenter registry points to a potential reduction in restenosis by a synergistic approach of DCA and stenting performed under routinely accessible angiographic guidance. Therefore, multicenter-based randomized clinical trials are clearly warranted to finally clarify the validity of this complex approach versus conventional angioplasty plus stenting.

Predicting coronary events with coronary calcium: Pathophysiologic and clinical problems

There is a significant relationship between the presence, extent and progression of coronary artery calcification (CAC) and cardiovascular (CV) events and mortality in both CV and renal patients and CAC scoring can provide improved predictive ability over risk factor scoring alone. There is also a close relationship between CAC presence and atherosclerotic plaque burden, with angiography studies showing very high sensitivity but poor specificity of CAC score for predicting obstructive disease. Nevertheless, there are objections to CAC screening because of uncertainties and lack of studies showing improved outcome. Furthermore, histopathology studies indicate that heavily calcified plaque is unlikely to result in a CV event, while the vulnerable plaque tends to be uncalcified or ‘mixed’, suggesting that calcification may be protective. This scenario highlights a number of paradoxes, which may indicate that the association between CAC and CV events is spurious, following from the adoption of CAC as a surrogate for high plaque burden, which itself is a surrogate for the presence of vulnerable plaque. Since studies indicate that arterial calcification is a complex, organised and regulated process similar to bone formation, there is no particular reason why it should be a reliable indicator of either the plaque burden or the risk of a future CV event. We suggest that it is time to divorce arterial calcification from atherosclerosis and to view it as a distinct pathology in its own right, albeit one which frequently coexists with atherosclerosis and is related to it for reasons which are not yet fully understood.

Intravascular ultrasonography in the evaluation of results of coronary angioplasty and stenting

The main advantage of intravascular ultrasonography (IVUS) over angiography in assessing the effect of coronary interventions is the ability of IVUS to directly visualize the vessel wall. IVUS often reveals a high residual plaque burden after angiographically successful angioplasty, and this can motivate the operator to use additional, more aggressive measures in an attempt to increase lumen dimensions. Studies using IVUS imaging before and after balloon angioplasty have shown that luminal gain after percutaneous transluminal coronary angioplasty (PTCA) results from a combination of plaque reduction and vessel wall stretch. Minimal luminal area and residual area stenosis after PTCA and stent deployment, as measured by IVUS, have been shown to be predictors of restenosis. IVUS studies have pointed to vessel shrinkage, not intimal hyperplasia, as the main mechanism of restenosis after PTCA. IVUS guidance of stent deployment has often revealed inadequate stent expansion despite optimal results on angiography, leading to high-pressure stent deployment with significant additional luminal gain. Restenosis rates may be lower with IVUS-guided stent deployment.